Decorative laminates are widely used in the cabinet, molding, furniture, consumer electronics, paneling, boating, recreational vehicles, and other industries. One conventional decorative laminate structure is formed from an at least partially transparent decorative film that is laminated to a desired substrate. The decorative film often includes decorative information such as the image(s) of wood grain, stone, leather, textile, fanciful designs, one or more colors in a pattern or otherwise, a human, an animal, nature, architecture, and the like. The film often is made from ingredients including one or more polymers. The decorative information often is on the inside face of the film while the outside face of the film bears a texture to help provide low gloss, a matted appearance, scratch and mar resistance, and/or anti-blocking resistance in printed roll, stack or other form in which a film face contacts an adjacent film face of the same or a different film. One or more additional layers may be incorporated into such a decorative laminate, either between the film and the substrate or otherwise, such as an additional decorative film, an underlay, an overlay, an adhesive, protective coating, and/or the like.
The decorative information is desirably applied onto the film using printing techniques such as ink jet printing, laser printing, gravure printing, offset printing, anastatic printing, silk screen printing, transfer printing, lithographic, flexographic, other printing methods, combinations of these, and the like. Typically, the film is textured on one major face, while the decorative information is printed onto the other major face. If the film is textured prior to printing, the film is considered to be pre-embossed. If the film is textured after printing, the film is considered to be post-embossed.
Relatively deep textures, e.g., those textures having an Ra surface roughness of over about 100 microinches, preferably over 120 microinches, and even over 150 microinches, are desirable in many applications as these tend to provide much better blocking resistance and scratch and mar resistance than lighter textures. Also, deeper textures provide very desirable visual and tactile properties.
However, there are significant challenges involved in preparing films having decorative, printed information on one face and deep texture on the other face. It is quite difficult to print decorative information onto the smoother side of a pre-embossed film bearing a deeper texture on the other side. Due to the deeper texture, such films tend to experience chatter or other tracking problems when transported through a printer. Chatter generally refers to an undesired, vibration of the moving film, especially side-to-side, repeated movement or jitter of a film. These problems can seriously compromise the quality of the printed information. Quite simply, many embodiments of conventional pre-embossed films with deep texture have not been as printer-compatible as might be desired. There is a bias in the decorative laminate industry, particularly under the relatively stringent commercial standards applicable to the decor printing industry, against trying to print onto such deeply embossed films.
The industry generally prefers to post-emboss printed films. In this technique, the film can be relatively smooth on both sides at the time of printing and have good tracking characteristics through the printer. The film is then embossed after printing.
Post-embossing involves some drawbacks, though. First, it involves an entire extra stage of manufacture that requires expensive equipment, facility space, utilities, and other resources, all of which add considerable expense to the manufacturing process. Also, post-embossing can be a bottleneck in the overall manufacturing line, adversely impacting throughput. The printed information is also put at risk, as extra handling is required for the film to traverse through the post-embossing stage of manufacturing. If the printed information is damaged or otherwise compromised during the embossing stage, scrap is produced and yields go down. Additionally, post-embossed texture is less permanent than pre-embossed texture. Under pressure and heat, which are typically used to form decorative laminates, a significant portion of post-embossed texture can be lost. Thus, a post-embossed film may have to be over-textured to meet a texture specification applicable to the laminated product. It is hard to control the uniformity of the embossing on the final product in this kind of scenario. There can be considerable variation, and specifications have to be less stringent to accommodate this.
Another technical solution is to use pre-embossed films that have a very limited degree of texture, e.g., an Ra surface roughness of under 90 microinches, even under 80 microinches, or even under 70 microinches. By limiting the texture on the “embossed” surface of a film, the pre-embossed film may exhibit acceptable tracking properties during printing. However, such light texture does not provide acceptable scratch and mar resistance and/or anti-blocking protection in many applications. Films bearing such light texture may also exhibit gloss levels that are higher than desired. Additionally, the visual and tactile sensations offered by these films may tend to be unappealing to consumers, particularly when the decorative information corresponds to natural surfaces such as wood grain, stone, leather, fabrics, and the like.
Another technical solution is to print the decorative information onto a separate film that is sufficiently smooth on both sides to be both printer compatible and ink receptive and then to incorporate this printed film into a decorative laminate that includes a separate, more deeply textured film as an overlay. This involves adding a whole extra component in the product and is accompanied by the associated extra stages of manufacture and resources to handle.
The industry could benefit significantly from a printer-compatible, pre-embossed film having a deeper texture.